The 4 C’s
Diamonds are one of the most desirable gemstones in the world. It’s sparkling elegance can command huge prices due to The 4 C’s. Colour, clarity, carat and cut.
Colour
The colour of a diamond is something everyone can see and a slight hint of colour can make a huge difference in a diamonds value. The industry standard scale used is GIA’s (The Gemological Institute of America). The scale is alphabetical from D-Z.
D is the highest grade and diamonds graded as D come with a premium as they have no colour in them at all. These are the most desirable diamonds on the colourless scale. As you go down the scale the colour changes to have hints of light yellow and/or brown. The value placed on diamonds as they go down the scale is less as they are seen as less desirable but as we know, the beauty is in the eye of the beholder.
Diamonds also come in all colours of the rainbow due to the chemicals present in their structure and these ‘fancy’ diamonds are graded on a different scale which focuses on saturation of colour. Fancy coloured diamonds are far more rare than diamonds on the colourless scale as only 1 in 10,000 diamonds has a fancy colour.
Diamonds graded in the fancy scale show colour beyond the grade Z if they are yellow or brown. Any other colour are graded on the fancy scale. The grading scale ranges from fancy light to fancy deep depending on the saturation and tones within the diamond.
The most rare colour of diamond is red. There are only a handful of red diamonds in the world. One of the latest red diamonds to sell at auction (graded as fancy-red) was a 1.56ct round brilliant cut which sold for a record breaking $4.2 million at the Philips auction in Geneva in May 2024 (Rapaport, May 2024).
Clarity
The clarity of a diamond is assessed on its internal and external features known as inclusions if they are internal or blemishes if they are external. Often people think of inclusions as negative but they are a natural part of most diamonds which we like to think of as Mother Natures finger print. It is incredibly rare to find a completely flawless diamond which is why they come with a high premium.
Clarity is graded on what types of inclusions are present, how many there are, how noticeable they are and where they are in the diamond. Of course a diamond could have one inclusion or many, every diamond is unique.
There are a number of different inclusions including crystal, feather, clouds, knots and pin points. Some are more noticeable than others for example, crystals are what people typically think of as an inclusion because they are black.
Depending how familiar you are with inclusions and looking at diamonds will depend how easily you can see inclusions. We find an untrained eye without magnification often sees inclusions from SI2 and lower and an untrained eye with magnification and guidance can see inclusions from SI1 and lower. Of course every persons eye is different and it depends on the individual inclusions themselves.
Carat
A little bit of science now! The term carat or carat weight are used to determine the size of a diamond. Diamonds are measured in metric carats which you will often see noted as ‘ct’ for short. One metric carat is 0.2g. The higher the carat weight of a diamond the more expensive it will be as that diamond is more rare than a smaller one.
Carat is often a more personal choice as not everyone wants a huge rock on their finger! Some people like a ring to sit lower on their finger and for that they will need a smaller diamond.
Cut
Cut is often mistaken for shape in The 4 C’s. It is actually grading how well the diamond has been cut and how well proportioned it is. People often underestimate and overlook the cut grade but it is actually (in some people’s minds) the most important of The 4 C’s as it determines how well a diamond sparkles and handles light.
As you can see from the diagrams, if light exists the diamond through the pavilion facets the diamond will look noticeably darker even if it were to have a high colour grade. This is because the light is not returning to your eye as it does in a diamond that has ideal proportions.
The other factors that contribute to the final cut grade are, polish, symmetry and proportions as mentioned before. To achieve the highest fire and brilliance from a diamond it is important to have a higher cut grade as possible for any shape of diamond.
For decades gemmologists have studied and improved the amount, size and shape of the facets determining that the modern round brilliant cut perfectly handles light. If you look at other shapes like emerald and baguette they do not sparkle like round brilliants as they have far fewer facets. Because of this, they tend to have a higher clarity grade as you can see right into the stone.
Diamonds will always hold a special place in the jewellery industry and serve as a beautiful reminder of our Earth’s natural wonders. When choosing your diamond, there is no right or wrong and should be guided by your personal preference only. Thank you for reading!
